I have seen in quite few places (one example here: http://pascalgamedevelopment.com/archive/index.php/t-1204.html) people doing this.
Embarcadero documentation says nothing about the position of the header in the file/stream after creating the stream.
Conclusion:
Since the documentation does not guaranty the position of the cursor, we should use 'Seek=0'. Even if now the cursor is placed at the beginning of the file, we will never know how this will change in time. Since Embarcadero does not document this, it looks like they reserve the right to change it.
TFileStream.Create just opens file handle and leaves file position where the Win32 put it after the handle was open - at the beginning on the file.
There's no need to Seek to 0 position; you are already there.
Related
I have written a custom external file handler (EXTFH), but there are some cases where I want to revert to the Micro Focus EXTFH. The cases are on a file by file basis (as opposed to a filetype by filetype basis).
My idea is that upon OPEN, I place a marker in the FCD that tells the subsequent operations (READ, WRITE, CLOSE) as to which EXTFH is in use.
My EXTFH has control and the logic can be very simple if there is a place in the FCD that is guaranteed to not be corrupted by MicroFocus.
Is there a place in the FCD (fcd2.h and fcd3.h) that I can mark an open file as being opened by my EXTFH?
My worst case is that I keep a list of the fcd->handle pointers that I have allocated and if I allocated it, then direct to my EXTFH. If not, direct to the MF EXTFH.
Here is the documentation from Micro Focus on EXTFH:
http://supportline.microfocus.com/documentation/books/sx20books/fhexfh.htm
That is older documentation, but is appears to be pretty much up-to-date.
[edit to clarify how we will use detect which to use: We will use the extension on the file name to determine which file handler to use. For instance, if the extension is: .xyz, then use our EXTFH, otherwise use MF EXTFH]. It appears we can check the filename on every fileio, but I think it would be cleaner if we just checked upon OPEN. For subsequent calls for that file, we would just check something in the FCD.
I have an application and posted to Cydia recently. It has been cracked by someone else and posted it in torrent sites. I have a binary checksum verification mechanism inside and they were able to create a new checksum file based on the changes they have made to the binary. They have edited two functions and decompiled it and posted it to torrents.
I saw that it's possible to see the actual implementation of functions and classes. But in order to edit the functions they have to find the address of that function and edit it via HEX EDITOR. I don’t want to make it "unhackable", but I really want to find out how they hack.
How can I edit a function in an iOS binary and re-compile it? For example I have a following method in one of my classes.
- (id) getSomething {
return #"Something";
}
I want to edit the return value of this function. Is that possible?
Usually, you don't "re-compile" it. Just feed the file to IDA, look for strings, function calls or whatever you are looking for and then use a hex editor or similar to edit the file on assembly level. In most cases it's enough to simply change a conditional jump into an unconditional jump or a nop (no operation). If you want to change return values, you have to put a little more effort into it, but in my experience you either edit the char sequence right inside the binary file, if it's specified as a constant or initial value - or you just write a completely new function and "copy" the assembler code of it into the original file. You just have to make sure your new function does not take more space than the original - or everything's getting a lot more complex.
I hope that's what you were asking for, otherwise just tell us which app you are talking about and we can look deeper into it :)
I'm working in a Delphi IDE expert and I wonder if it's possible add new items to the code completion combobox displayed by the Delphi IDE when the user press CtrlSpace
UPDATE:
What I need is add items to the code completion list based in a specified type.
example suppose which I have a type called TMytype, what I want to do is add addional items to the code completion list when the user type a variable of the type TMytype
check this image
I found your question somewhat confusing but if you are in search of credible source on "Custom Live Templates" and the like on Delphi, head to the blog of Cary Jensen here.
Edit:
Looking forward to further improvement of the scope of the question, I suggest here another direction to explore:
Source code manipulation using IOTAEditor, IOTASourceEditor, IOTAEditReader and the like
Some Parsing for sanity check prior to apply any modification.
Adoption of Client DataSet as a format to store data (It's serializable) to simplify the coding of IDE editors.
Perhaps I haven't fully grasped the extent of what you are asking here, but you can add templates simply by going to 'View|Templates' from the Delphi IDE. This then opens a template viewer. Press the '+' icon. It opens a template1.xml document which you can then edit so create your new item.
If you wish to do this programatically, just add an xml file (of the same format) to the ..\RAD Studio\code_templates folder.
I am getting a cascading set of "EClassNotFound" errors in in my Delphi 2007 project. Doesn't seem to be caused by the missing Name property value as often is the case, and though adding RegisterClass(XXX) in the initialization section(s) fixes the EClassNotFound error at hand, another one follows it seemingly indefinitely.
I finally cracked open the DFM file in text editor, and it looks likely corrupted to me (lots of non-ASCII characters amidst form element names, and very "unstructured" looking when compared to what I'm used to seeing in a DFM file). (I'd post a same here but not sure that's OK, w/the non-aSCII, so will hold off).
The form loads fine, and seems to compile / syntax check OK too, but once I run it, trouble.
Going back to early versions of it in SVN, it looks like it's been in this state for some time, which makes me think that either A) the DFM file isn't my problem, or B) the Delphi form-streaming is quite fault-tolerant/robust (Bonus Question: Which is it?).
If the DFM file is the problem, and is corrupted, rolling back will have to be a roll-back WAY back, and that's gonna be expensive. Given that the IDE can still load it, is there any utility that can clean up the file?
Or, am I totally off base w/the DFM as primary suspect?
Thanks folks for the input. Forgot about the binary/text options w/DFM files, so that was helpful. It looks like the DFM itself is not corrupted.
Still having the EClassError issue though. re: It being missing property values, or referencing non-existing properties, etc., a further question: Is the class the error is given for (currently TnxSqlUpdateObject, but probably more waiting in the wings if experience thus far is consistent) usually/always the actual "culprit" class/object?
For instance, right now my main form has four references to TnxSqlUpdateObject, w/those actually dropped on the form. If I put RegisterClass(TnxSqlUpdateObject) in the initialization section, it runs fine for that EClassNotFound error but then goes on to the next one (in this case, TStringField).
I have reinstalled the NexusDB components in this case, and also built a new project using some of the components I thought might be the problem. It compiles and runs fine, UNTIL I add this other form from my real project (which, in turn, unfortunately references quite a few others).
SO, it sounds like my real issue is how to methodically diagnose and fix any and all EClassNotFound errors?
I get this error if a component is on the form, but doesn't have an entry in the form definition in the source file too. Most often when I've copied and pasted from another form. Simplest solution is to select the component, cut it, then paste it back. When you save, the component's unit will be added to the source, and when you run it again it will all be okay.
Well, a dfm file could be binary or tekst (as I'm correct from version 4.0).
You can check this by right click on the form and check the Text DFM flag.
If a dfm file is corrupt, tou can try to fix it by removing all suspicious lines.
Be sure to leave the object .. end sets intact and you probably only loose some property values.
By the way, the dfm file should look like this (to get an idea of the general structure):
object Form5: TForm5
Left = 0
DesignSize = (
426
652)
object Button1: TButton
Left = 343
end
object Memo2: TMemo
Anchors = [akLeft, akTop, akRight, akBottom]
end
end
If it does not look like that you are probably editing the binary file.
If you have a recent compiled exe that works, you can use a resource-editor, like PE Explorer, to get the dfm-definition. Then you can compare the one from the exe with the one that you now have.
I believe there is tools to convert binary dfm-files to text-files too. This will give you a better view on the file, and help you decide if it's really corrupted or not. I see Felix has something on the topic.
If the Delphi IDE shows the form ok without errors, I can't believe there is a corruption-error. Could there be a package problem? Do you use runtime-packages?
Update:
Hvae you tried Eurekalog or madExcept or something similar to get a more detailed error message with callstack and memorydumt? Maybe that will give you some clue about the problem.
But generally i think this error comes from missing runtime package, or a missing unit in the uses-clause. If you think you know witch component causes the error, search the source for the call to RegisterClass( ), and see if that unit somehow is included in the projcets uses-clause. If not, add it and try again.
If you can load the form in the Delphi IDE the DFM resource is not corrupted. Delphi uses the same code to load the DFM as the final executable will use, so I think that won't be the reason.
You can open the DFM in the Delphi IDE directly (if the corresponding pas file is not open), or you can use Alt+F12 to switch between form view and text view of the DFM. In this view the structure should be sane, with correct indentation and so on.
As Gamecat pointed out you can use the command in the form popup menu to toggle the DFM storage format. Leave it as text for Delphi 5+, it works better this way with SVN.
As for the cause of your runtime problem - I have no idea...
Edit: After your ruling out the DFM as the source of the problem I can only assume that an important unit in the uses list is missing, which can only happen if not all the components on your form have a corresponding member field. You should check that all the components referenced in the DFM are also in the form, even when you do not access them in your code. This will in turn cause Delphi to add any missing units to the uses clause when the file is saved. Manually registering components should not be necessary if the form class has references to all the components in the DFM.
For a quick check you could create a test form, drop all of the components that your "problem" form has onto it (one instance is enough), and check whether this works.
This can happen in case you have changed one of your custom components and removed a property from it. The property is stil in the DFM and Delphi tries to initialize it.
Try to remove manually parts from your DFM so you can pinpoint which component is causing the problem.
Try this:
Make backup first
Right click on form in designer; uncheck "Text DFM"
Save
Right click on form in designer; check "Text DFM"
Save
near the top of the code i see things like,
btn_dropdown._visible = false;
mcMenuBkg._visible = false;
but I can't find these assets anywhere in the library or in any code, how does this make any sense?
The movie clips in the library that look the same have different names and I can delete them entirely and they still show up when I compile and run, or I can add trace statements into their code and they never get called.
where on earth are these assets defined?
In theory, any clip you see at runtime could be dynamically created, by making an empty MC and drawing in whatever contents you like with the drawing API. However, if you see clips in the library that are similar to what's showing up at runtime, then it's very unlikely that that's happening.
Your first step should probably be another look through the library. Remember that instance names don't have to be the same as MC names; even if something is called "Menu Holder" in the library there might be an instance of it somewhere called "mcMenuBkg" or whatever. But the fact that you can delete stuff without changing the output is mysterious.
So, other possibilities: contents are being loaded externally, or imported via runtime sharing. If feasible, try moving your SWF to a temp directory and running it from there; that should break all loads (unless contents are loaded from a remote URL).
Or, you're looking at the wrong clips in the library. If it's a crufty project there may be unused stuff in there. Try expanding the library wide enough to see the "Use count" column, and select "update use counts" from the library menu. Anything with a count of 1 or higher is part of your FLA's stage content - either it's sitting on the main stage or it's a child of something that is. Clips with a use count of 0 may still be used if they have a linkage ID; they could be created at runtime with attachMovie(). However, for any clip with a use count of 0 and no linkage id, it's safe to assume that it's unused, and irrelevant to what happens at runtime.
If none of that helps, the only things that come to mind are sanity checks... open up everything on the stage and every clip with a linkage id, and check for empty/invisible MCs. Check the Movie's export settings to make absolutely sure the SWF you're checking is the same one being published. And just for grins, open up the "Scenes" panel and make sure that some diabolical fiend hasn't put important content on a separate scene where no sane man would look for it.
Vague answer for a vague question. :D Hope it helps...
You can create movie clips with code dynamically.
This means that you may not have them in your assets if you are unable to find them.
You can create any type of symbol using a constructor out of thin air with actionscript alone.
I would search the code for one of these
var mybutton:SimpleButton=new SimpleButton();
If they're being set to
_visible = false
you won't see them anyway - and as ActionScript 1/2 doesn't do runtime error reporting, the Flash player won't complain if they're not actually there on the stage. If they're not being used, just delete them.